A paper feeder removably attachable to an image forming apparatus having a display unit wherein the number of copies on display is incremented upon copy paper reaching a specified position in a path of transport. The paper feeder comprises paper feed means (11,12) for transporting the copy paper to the apparatus, reference distance memory means (54) for storing therein a reference distance from a predetermined feed position of the paper feed means to the specified position in the apparatus, means (15) for measuring the amount of transport of the copy paper from the predetermined feed position, counting means (54) for checking whether the amount of transport measured by the measuring means has reached the reference distance and incrementing the number of paper sheets fed to the apparatus upon the amount of transport reaching the reference distance, and display means (53) for indicating the number of paper sheets counted by the counting means.